使用 C++ 将整数写入二进制文件?
我有一个非常简单的问题,这对我来说很困难,因为这是我第一次尝试使用二进制文件,但我不太了解它们.我要做的就是将一个整数写入二进制文件.
I have a very simple question, which happens to be hard for me since this is the first time I tried working with binary files, and I don't quite understand them. All I want to do is write an integer to a binary file.
我是这样做的:
#include <fstream>
using namespace std;
int main () {
int num=162;
ofstream file ("file.bin", ios::binary);
file.write ((char *)&num, sizeof(num));
file.close ();
return 0;
}
如果我做错了什么,你能告诉我吗?
Could you please tell me if I did something wrong, and what?
给我带来麻烦的部分是file.write,我不明白.
The part that is giving me trouble is line with file.write, I don't understand it.
提前谢谢你.
推荐答案
给我带来麻烦的部分是file.write,我没有明白了.
The part that is giving me trouble is line with file.write, I don't understand it.
如果您阅读 ofstream.write()
方法的文档,您会看到它需要两个参数:
If you read the documentation of ofstream.write()
method, you'll see that it requests two arguments:
一个指向数据块的指针,其中包含要写入的内容;
a pointer to a block of data with the content to be written;
一个整数值,表示此块的大小(以字节为单位).
这条语句只是将这两条信息提供给ofstream.write()
:
This statement just gives these two pieces of information to ofstream.write()
:
file.write(reinterpret_cast<const char *>(&num), sizeof(num));
&num
是数据块的地址(在这种情况下只是一个整数变量),sizeof(num)
是这个块的大小(例如在 32 位平台上为 4 个字节).
&num
is the address of the block of data (in this case just an integer variable), sizeof(num)
is the size of this block (e.g. 4 bytes on 32-bit platforms).
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